1. Field of the Invention
The present invention relates to a method for manufacturing a flip-chip (FC) type semiconductor device featuring nickel (Ni) electrode pads, and also relates to a plating apparatus used in the manufacturing method.
2. Description of the Related Art
An FC type semiconductor device has been developed to meet the demands of higher performance, smaller and lighter size, and higher speed for a piece of small electronic equipment, such as a mobile phone, a mobile personal computer or the like. The FC type semiconductor device has a plurality of electrode pads arranged on a top surface thereof, and a plurality of metal bumps bonded to the electrode pads. In this case, each of the electrode pads may be formed by a suitable metal material, such as aluminum (Al), copper (Cu) or the like. On the other hand, each of the metal bumps may be composed of various metal materials, such as tin (Sn), tin alloy, gold (Au), copper (Cu), lead (Pb) or the like, and serves as an electrode terminal.
The FC type semiconductor device having no metal bumps may be commercially distributed and circulated in a market as a part for manufacturing an electronic package, such as ball grid array (BGA) packages or the like. In this case, the metal bumps are bonded to the respective electrode pads of the FC type semiconductor device later on. When either tin (Sn) or tin alloy is selected as a metal material for the metal bumps, tin atoms may be diffused so as to penetrate into the interior of the FC semiconductor device through the electrode pads, and the penetrated tin atoms may cause damages in the FC semiconductor device.
For example, as disclosed in JP-H06-232136-A, JP-H09-069524-A and JP-H11-214421-A, it has been proposed that a nickel (Ni) layer be formed as a barrier layer on the electrode pad to prevent the penetration of the tin atoms into the interior of the FC semiconductor device.
The formation of the Ni layer can be carried out by using either an electroplating process or an electroless plating process. In either case, when either the electroplating process or the electroless plating process is completed, the Ni layer is drenched with an aqueous nickel-plating solution, and must be washed with pure water to remove the aqueous nickel-plating solution therefrom so that the Ni layer can be prevented from being corroded with aqueous nickel-plating solution.